Unfairly treatment from the employer

I have a really annoying issue with Pick'n Pay Something Nice at 209 Blue Downs Way, Tuscany Glen Blue Downs, 7100.

The story goes this way. So my uncle on the 20th September 2019 got injury at work, a grocery routine fell on top of him and his left ankle got broken. Also the back of his left leg cracked. He was sent to Netcare Hospital in kuils river then got operated after 1 week because he was swollen they couldn't operate him the same day. They had to ***** the broken ankle and bandaged the cracked part. So he had to be off duty from the day of the incident which is the 20 September 2019 until the 23 of March 2020 and then he resumed at work on the 24 March 2020. But he got paid his salary in full while he was off duty by the employer until he resumed at work. So he took doctors certificates and went to labour department and received a resumption report claim form which was supposed to be completed by his employer and he did complete the form but it is untidy and incomplete. The employer took the original document and gave my uncle the copy of the form scanned together with an invoice at the back as incomplete as it is. Then he told my uncle he is going to email the form to labour which he didn't. Period off duty is not complete, claim number is not written, there's no date filled and the from is scratched out some words hence I am saying it is untidy. So my uncle went to labour to enquirer if they got the form from my employer and he was told that no form was received. My uncle has been begging his employer to fill in the blank parts complete after he noticed the form is incomplete. Ever since he started working there he never got any leave day's it is now 4 year's, when he is asking about leave day's he is being threatened and told that he is owing the company the money he was paid when got injured and there is no increase no bonus he gets only off days.

Please please please this is too much my uncle needs this to be resolved as soon as possible.